alexreardon

/* data-transfer-item-list.spec.ts */

import invariant from 'tiny-invariant';

test('add(data, format) should add a string item', done => {
  const list = new DataTransferItemList();

  list.add('Hello world', 'text/plain');

  const item: DataTransferItem = list[0];

alexreardon

// This file polyfills DragEvent for jsdom
// https://github.com/jsdom/jsdom/issues/2913
// This file is in JS rather than TS, as our jsdom setup files currently need to be in JS
// Good news: DragEvents are almost the same as MouseEvents

(() => {
  if (typeof window === 'undefined') {
    return;
  }

alexreardon

function add(a: number, b: number): number {
  return a + b;
}

type MyParameters<TFunc extends (...args: any[]) => unknown> = TFunc extends (
  ...args: infer TArgs
) => unknown
  ? TArgs
  : unknown;

alexreardon

// This file polyfills `Element.prototype.scrollBy`
// scrollBy(x-coord, y-coord)
// scrollBy(options)
(() => {
  if (typeof Element === 'undefined') {
    return;
  }
  if (typeof Element.prototype.scrollBy !== 'undefined') {
    return;
  }

alexreardon

const interactions: number[][] = [];

function sum(values: number[]) {
  return values.reduce((acc, current) => acc + current, 0);
}

function average(values: number[]): number {
  if (!values.length) {
    return 0;
  }

alexreardon

export {};

const allCollectedFps: number[][] = [];

function sum(values: number[]) {
  return values.reduce((acc, current) => acc + current, 0);
}

function average(values: number[]): number {
  if (!values.length) {

alexreardon

function average(values: number[]): number {
  const sum = values.reduce((acc, current) => acc + current, 0);
  return sum / values.length;
}

export function standardDeviation(values: number[]): number {
  /** https://www.mathsisfun.com/data/standard-deviation-formulas.html
   * 1. Work out the Mean (the simple average of the numbers)
   * 2. Then for each number: subtract the Mean and square the result
   * 3. Then work out the mean of those squared differences.

alexreardon

function waitForFrames({
  frames,
  done,
}: {
  frames: number;
  done: () => void;
}): () => void {
  let frameId: number | null = null;
  let remainingFrames = frames;

alexreardon

import { bindAll } from 'bind-event-listener';

import type { DragLocation } from '../internal-types';

type CleanupFn = () => void;

/** Set a `style` property on a `HTMLElement`
 *
 * @returns a `cleanup` function to restore the `style` property to it's original state
 */

alexreardon

this binding

• this is the runtime context of a function.
• this is determined by the call site
• the same function can be executed with different this runtime contexts. You can think of this as another arguement to the function
• Comparison: scopes are generally defined at compile time (exception: eval)

const person = {
 name: 'Alex',